No particular experience here, but all that comes to mind are the mic pre's.
Might be worth mentioning what features if any, you are looking for.

My '58 ESP catalog lists:
1510A Preamplifier $99
1511A Preamplifier $85
1566A Preamplifier $90
1567A Mixer Preamplifier $198

...along with 1568A/1569A/1570A amps, so the former are presumed contemporary to those.

The 1567A spec sheet: "Insertion of the 12864 accessory plug will convert either of two low level inputs to phono facility and provide the proper RIAA equalization for magnetic pickups."